Conventional pellets for air, gas and spring guns are made of lead or a lead alloy which is soft enough not to score or damage the bore surface of the gun barrel during passage therealong. Unfortunately such conventional pellets, because they are made of such soft metal, are easily damaged and deformed out of shape prior to use, to such an extent as to render them unfit for use or seriously to impair their accuracy in use. Indeed lead pellets for match shooting are required to be individually packaged to minimise damage.
Furthermore conventional lead pellets have the additional disadvantage of a high coefficient of friction which can result, in use, in high energy losses by friction with the gun barrel bore surface during passage therealong. Attempts have been made to reduce these frictional losses by coating the pellet with a lubricant, but this lubricant coating is easily damaged and can cause fouling of the gun bore with subsequent loss of accuracy.
Other attempts have been made to solve these problems by the provision of pellets made wholly of plastics but these plastics pellets have only a short range and poor penetrative power due to lack of weight, stability and hardness. Alternative proposals have been felt based metal pellets which have had poor sealing with the gun bore surface and a consequent drop in muzzle velocity, and steel darts with a fibrous base, which can seriously damage the gun bore surface.
Additionally such conventional pellets when made to fit standard Imperial size bores such as 0.177 inches and 0.22 inches will not fit corresponding equivalent Metric size bores such as 4.5 millimeters and 5.5 millimeters. This is because a 0.177 inch bore pellet is slightly over size for the equivalent 4.5 millimeter bore which is not exactly the same size as the 0.177 inch bore. This means that Metric and Imperial size pellets are not interchangeable and hence Imperial and Metric size bores require corresponding size pellets for accuracy.